1. Field of the Invention:
This invention relates to a process for producing a rolled-in type emulsified fat and oil composition. More particularly, it relates to a process for producing a stable rolled-in type emulsified fat and oil composition improved in puffing properties and nutritional value.
2. Description of the Prior Art:
A rolled-in type emulsified fat and oil composition to be used in, for example, puff pastry, danish pastry or croissant would form thin layers in a dough, through repeated folding and rolling, to thereby impart a large volume and a crispy texture to the final baked product. When no thin layer structure can be adequately formed, neither the desired volume nor the crispy texture can be achieved. In order to form the aimed thin layers, a rolled-in type emulsified fat and oil composition should have an appropriate consistency, elasticity and flexibility suitable for each dough. Rolled-in type emulsified fat and oil compositions may be broadly classified into a water-in oil type emulsified composition including margarine and an oil-in-water type one. Since the former has a continuous phase comprising a fat and oil, it shows a large change in consistency depending on temperature. Thus it is required to produce such products with the use of a specific device, for example, a complecter or a high-pressure combinater or to employ such a fat and oil composition as to cause a smaller SFI change depending on temperature in order to widen the application temperature range thereof, though the latter method brings about a poor meltability in the mouth. On the other hand, since the latter has a continuous phase comprising water, it shows less change in consistency depending on temperature and thus has a wide application temperature range. However it is required to incorporate a fat and oil thereinto at a high content in order to give a consistency suitable for a dough. It is further required to add a thickener to the aqueous phase thereof. Furthermore it is required at present to add a preservative thereto to thereby improve the shelf stability. With the recent concern for health, the consumption of fat-rich products such as puff pastry, danish pastry and croissant has been stagnant. In order to counteract these situations, it is required to lower the fat and oil composition content of a product or the fat content of a rolled-in type emulsified fat composition. However every known process therefor is accompanied by some troubles such as failure to form the necessary layer structure, an undesirable texture or a poor volume.
As an example of an oil-in-water type emulsified composition containing protein. U.S. Pat. No. 4,012,533 discloses a whipped cream dessert comprising 10 to 32% of a fat and 1.5 to 7% of a composition of a water-soluble protein, a sweetener, an emulsifier and a gum stabilizer, while Japanese Patent Laid-Open No. 79849/1982 discloses an oil-in water type emulsified composition wherein a partially hydrolyzed soybean protein is used as an emulsifier. However, the former product is one produced by dissolving the small amount of water-soluble protein in a large amount of water, emulsifying the resulting solution with the use of the emulsifier and stabilizer and then whipping the obtained emulsion, and the latter one is one emulsified by using the partially hydrolyzed soybean protein of an improved emulsifying capability. Thus both of these prior products are different from the rolled-in type emulsified fat composition of the present invention wherein a common protein is employed at a high content in an oil-in-water type emulsified composition. It is usually very difficult to stably emulsify a composition of a high protein content. In the case of a kneaded-in or folded-in type oil-in-water type emulsified composition comprising a fat, a starch, water and a gum disclosed in Japanese Patent Laid-Open No. 166345/1986, for example, stabilizers, namely, the starch and gum are added. However the product thus obtained has a gelationous and poor texture. When it is to be rolled in, in addition, it is liable to adhere to the dough to thereby form no layer.